Java Use-API: No use provider could resolve identifier

[Former Community Member]

Hi everybody,

I'm experimenting with the new Java Use-API [1] but I'm having trouble getting it to work.

1. I have a component here: /apps/abc/components/modular/C03-topbanner/
2. Following the instructions, I put my .java file here: /apps/abc/components/modular/C03-topbanner/C03_topbanner.java
3. The package name in the java file is: apps.abc.components.modular.c03_topbanner (replacing the - with _ as described)
4. The class name is C03_topbanner
5. Within my sightly file (/apps/abc/components/modular/C03-topbanner/C03-topbanner.html) I'm calling it like so: data-sly-use.topbanner="c03_topbanner"
6. This gets me the extension: org.apache.sling.api.SlingException: Cannot get DefaultSlingScript: No use provider could resolve identifier: c03_topbanner
7. I've tried a few variation with file/package/class names but it never seems to work... The way I understand it from the docs is that just the package name has to be the same as the use class

Any ideas what I could be missing?

[1] http://docs.adobe.com/docs/en/aem/6-0/develop/sightly/use-api-in-java.html

[Knennigtri · Accepted solution]

The data-sly-use attribute uses the class name for java files, which are case sensitive. Looks like you used 

data-sly-use.topbanner="c03_topbanner"

Rather than

data-sly-use.topbanner="C03_topbanner"

Hopefully that fixes your error.

[Paul_McMahon]

Does you class implement the WCMUse interface, and does it have an activate method? I have seen where that was an issue that generated the same error. 

[Former Community Member]

Yes. Here's my dummy code so far:

package apps.abc.components.modular.c03_topbanner; import com.adobe.cq.sightly.WCMUse; import com.day.cq.wcm.api.components.DropTarget.CSS_CLASS_PREFIX; public class C03_topbanner extends WCMUse { private String cssClass; @Override public void activate() throws Exception { cssClass = DropTarget.CSS_CLASS_PREFIX; } public String getCssClass() { return cssClass; } }

[Former Community Member]

I got it to work now. I'm actually not sure what solved it in the end because I was pretty sure I had tested all these combinations. I changed the package and class name to "C03_topbanner". 

[b7wilso]

I am having a similar issue was wondering if someone could help.

    Component is located in /apps/global-web/components/content/relatedlinks/
    .java located in /apps/global-web/components/content/relatedlinks/MFPF.java (which extends WCMUse and I Override activate() )
    package name is apps.global_web.components.content.relatedlinks
    class name is MFPF
    sightly file (/apps/global-web/components/content/relatedlinks/relatedlinks.html) calls the java class as such: data-sly-use.mfpf="MFPF"

I actually shortened the class name down to MFPF in case there was some sort of weird length limit and have tried multiple variations.

Any thoughts?

[Former Community Member]

Have you tried commenting out everything to narrow it down? I've had the same error message one time and it turned out there was just a java error that never showed up anywhere..

[Feike_Visser1]

Do you see your class to be compiled in /var/classes?

Otherwise I would try to move it to an OSGi-bundle to see if that works, then you know the Use-class is fine.

[b7wilso]

Thanks for the responses guys.  I have stripped it down to bare bones to try and get it to compile so this is what I have in the class currently:

package apps.global_web.components.content.relatedlinks

import com.adobe.cq.sightly.WCMUse;

public class MFPF extends WCMUse {
    private String testVal;

    @Override
    public void activate() throws Exception {
        //testVal = "I can write a class that actually works!";
    }

    /*public String getTestVal() {
        return testVal;
    }*/
}

I just checked var/classes and no I do not see anything in there.  Would it be in/near the root or would it setup a similar folder structure to the one that is existing in there (in this class's case apps/global_web/etc...) ?

[b7wilso]

OK, so we found the error before dropping it over in an OSGi bundle, no semi-colon on the package.

[Feike_Visser1]

Nice one! :-) Great that this is now resolved.